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.Dd December 7, 2020
.Dt PROTOCOLS 5
.Os
.Sh NAME
.Nm protocols
.Nd protocol name data base
.Sh DESCRIPTION
The
.Nm
file contains information regarding the assigned protocol numbers
used by IPv4 and IPv6 to identify the next level protocol.
For each protocol a single line should be present
with the following information:
.Bd -unfilled -offset indent
official protocol name
protocol number
aliases
.Ed
.Pp
Items are separated by any number of blanks and/or
tab characters.
A ``#'' indicates the beginning of
a comment; characters up to the end of the line are
not interpreted by routines which search the file.
.Pp
Protocol names may contain any printable
character other than a field delimiter, newline,
or comment character.
.Sh FILES
.Bl -tag -width /etc/protocols -compact
.It Pa /etc/protocols
The
.Nm
file resides in
.Pa /etc .
.El
.Sh SEE ALSO
.Xr getprotoent 3
.Rs
.%R RFC 2780
.%D March 2000
.%T "IANA Allocation Guidelines For Values In the \
Internet Protocol and Related Headers"
.Re
.Rs
.%R RFC 5237
.%D February 2008
.%T "IANA Allocation Guidelines for the Protocol Field"
.Re
.Sh HISTORY
The
.Nm
file format appeared in
.Bx 4.2 ,
describing the "known protocols used in the DARPA Internet".
.Sh BUGS
A name server should be used instead of a static file.
